First time computer builder

Hey guys I'm planning on getting a new computer but this time I thought Id build it as Ive been told its cheaper and you can get a better system for less.

I looked around newegg and found some parts and wanted your opinion on them now this computer is geared towards gaming and my limit is around $900, if anything is out of place or you think theres something better that can be substituted please let me know

TY for the tips shadowfold and planet I wasnt sure which case would hold everything and get good ventilation and such but i had heard a lot of good things about that case so I thought might as well go with one i know will hold it all though if you have a better one i will gladly swap it out.

I'd personally get a great case now and less good parts... Just so that you have a great (and good looking) case for the next XX years... Tech evolves fast... cases don't so much... That's why when I get my PC, I'm getting the HAF 932 ... I know 155$ is a lot more than the 75$ + ~25$ ship is, but IMO it is worth the extra 55$

There were a few questions I came up with for after I build the computer, Do I have to buy a copy of windows xp for the new system? is there any way I can get the early windows 7 on it? Also do I have to partition my new hardrive? And if i did use windows 7 would my xp games still be compatible with it? Thank you in advance

Also, that PSU is a great deal, since it's modular, but it's only 500W. The video card recommends 500W minimum, add that with your 95W CPU and whatever else and you may go over 500W, so you may want something with a bit more power, although I know modular PSU's over 500W are expensive as crap.
I assume that you want the blu-ray drive for some reason unknown. Unless BRD were becoming common currency, you'd never catch me paying over $100 for a disk drive.
Last, you may want to get a fan for your optional fan bracket on the side panel. I bought a couple of these for my CM Storm Sniper's side panel. They're really good, Logisys 120mm, 4 blue LED's to match the ones on your front fans, only $7 with free shipping.

Also, that PSU is a great deal, since it's modular, but it's only 500W. The video card recommends 500W minimum, add that with your 95W CPU and whatever else, so may go over, so you may want something with a bit more power, although I know modular PSU's over 500W are expensive as crap.
I assume that you want the blu-ray drive for some reason unknown. Unless BRD were becoming common currency, you'd never catch me paying over $100 for a disk drive.
Last, you may want to get a fan for your optional fan bracket on the side panel. I bought a couple of these for my CM Storm Sniper's side panel. They're really good, Logisys 120mm, 4 blue LED's to match the ones on your front fans, only $7 with free shipping.